Gear set



A ril 11, 1939. J. M. WEYDELL GEAR SET Filed Oct. 26. 1936 INVENTOR. J59: /7 ifiq gfu,

ATTORNEY) Patented Apr. 11, 1939 2,153,856

GEAR SET Jarl It'll. Weydell, Indianapolis, Ind, assignor of one-half to Edward E. Stout, indianapclis, Ind.

Application October 26, 1936, Serial No. 107,563

4 Claims. (Cl. 74-4?) It is the object of my invention to produce a element which, when functioning as the driving change-speed transmission mechanism gear-set element, tends to drive the other two coaxial eleadapted to interconnect two relatively rotatable ments in the same direction. As I desire the 7 members in such away that the speed-ratio which speed-changing drive which the transmission the gear-set provides will depend upon which of provides to be a speed-reducing drive, I connect such relatively rotatable members is the driving the planet-gear carrier to the electrical unit. In member and which the driven member. More such an arrangement, the direction in which the specifically, it is my object to produce a planetary smaller sun gear tends to rotate will depend upon or epicyclic gear-set which may be used to con- Whether the larger sun gear or planet-gear car- 10 meet an internal combustion engine with an elecrier is the driving element. To control the transl0 trical unit adapted to function either as a motor mission in accordance with the direction in which to crank the engine or as a generator to create the smaller sun gear tends to rotate, I provide an electric current when driven by the engine. that sun gear with two series of ratchet clutch- A further object of my invention is to equip such tee h one co-operating with a stationary part a gearset with provisions which will function and the other with a corresponding series of I automatically to provide a speed-reducing drive teeth on the larger sun gear, and I so arrange when the electrical unit is cranking the engine clutch-teeth that their ratchet action will and a direct drive when the engine is driving the tend to move the smaller sun gear into clutching electrical unit. engagement with the stationary part when the In any epicyclic or planetary gear train, there planet-gear carrier is the driving element and 0 are three relatively rotatable, coaxial elements into clutching engagement with the larger sun one of which, when functioning as the driving gear when it is the driving element. element, will tend to rotate the other two in the The accompanying drawing illustrates my insame direction as that in which it rotates. vention as applied to interconnect an internal Either of such other two elements, when acting combustion engine and a motor-generator unit, 25 as the driving element,'will tend to rotate the Fig. i being a side elevation of one end of the third element in the reverse direction. In pracengine with parts of the transmission broken ticing my invention, I connect one of the two away and Fig. 2 being a vertical section on the rotatable members between which the transmsline 2-2 of Fig. showing the connection of 0 sion is to act with that one of the three coaxial transmission to the motor-generator unit. transmission elements which, when acting as the The transmission for the gear-set illustrated driving element, will tend to rotate the other two in the drawing comprises two coaxial sun gears elements in the same direction; and I connect iii and H, the former being smaller than the latone of such other transmission-elements to the ter, and a planet-gear carrier H2 in which are second rotatable member. In such an arrangemounted one or more pairs of planet pinions I3 35 ment, the direction in which the third element and it. The two pinions i3 and it of each pair of the transmission tends to rotate will depend of planet pinions are rigidly interconnected and on which of the two rotatable member is the mesh respectively with the sun gears it and Il. driving member and which the driven member. In use for the DH D indicated Bibi-7V9, the

To effect the desired automatic control of the gear-set just described is conveniently supported 40 speed-ratio which the transmission afiorcls, I profrom one end of the crank shaft it of the envide means operative in accordance with the digine i'l. While the transmission may be mountrection in which the said third transmission eleed directly on the end of the crank shaft, I prement tends to rotate to connect said third elefer to mount it upon an extension in the form of ment either to a stationary part or to one of the a sleeve H which is counterbored for the recep- 45 other transmission elements to effect a direct tion of the front end of the crank shaft it, which drive. is keyed thereto, and which may be held in place In the practical application. of my invention by a bolt i5 extending axially through the sleeve specifically described in this application, I preand into a screw-threaded recess in the crank fer to employ a planetary gear-set of the type shaft. The smaller sun gear til is rotatably 50 comprising two coaxial, external sun gears and a mounted on the sleeve it, while the larger sun planet-gear carrier coaxial with the sun gears gear ii is mounted for rotation with the sleeve, and carrying one or more pairs of planet gears as by means of splines 2d. The planet-gear carmeshing with the sun gears. In such a transrier 52 may be supported on the hub 2! of the 55 mission, the larger of the two sun gears is the gear II and is formed exteriorly to provide a 55 pulley for the reception of a belt 23 connecting the carrier to the pulley 24 of the starter-generator unit 25.

Associated with the transmission is a stationary part, here shown as a collar 21 secured to the front face of a boss 28 on the engine crank-case. The collar 21 and the sun gear II! are provided with interengageable ratchet clutch teeth 30, as indicated in Fig. 1. In addition to the clutch teeth engageable with the collar 21, the sun gear It is provided on the opposite side with a second series of ratchet clutch teeth 3| engageable with a corresponding series of similar teeth 32 on the adjacent side of the larger sun gear II.

The smaller sun gear I0 is axially slidable on the sleeve I8 between a position in which it is associated with the collar 21 and a position in which it is associated with the other sun-gear I I. Some means, such as a snap-ring 35 carried in a groove in the bore of the sun gear II! and cooperating with two axially spaced grooves on the sleeve 52, is desirably provided for tending to hold the sun gear in each limit of its axial movement on the sleeve I8 until it is definitely forced therefrom by the action of one or the other sets of ratchet teeth.

ihe sun gear II is shown in the drawing in the position it occupies when the pulley 24 is driving the belt 23, the direction of rotation being indicated by the arrow in Fig. 2. As the planet-gear carrier I2 rotates in a clockwise direction, the resistance of the crank-shaft I6 to rotation tends to cause the smaller sun gear ID to rotate in a counterclockwise direction. The ratchetteeth 3d are so inclined as to prevent rotation of the sun gear in a counterclockwise di rection; and, as a result, the sun gear II, and with it the crank-shaft, is driven in a clockwise direction at a reduced speed, the extent of the reduction depending upon the relative sizes of the various gears.

When the engine I? begins to operate under its own power, the sun gear II becomes the driving element of the transmission; and, as previously indicated, it tends to rotate both the smaller sun gear Ill and the planet-gear carrier I2 in the same, or clockwise direction. Rotation of the sun gear It? in a clockwise direction causes the ratchet-teeth 38 to force it to the right from the position shown in Fig. 1, thus bringing the clutch teeth SI into engagement with the clutch teeth 32 on the sun gear II. Since the sun gear II is larger than the sun gear II], the latter tends to rotate at a more rapid rate than does the sun gear Ii, or to rotate relatively to the gear II in the same direction as that in which the gear II is itself rotating. The interengaging clutch teeth i i-32 are therefore shaped to prevent clockwise rotation of the gear III relative to the gear I I. When the teeth 3IJ3I are engaged, the two sun gears I6 and II are compelled to rotate at the same rate and the gear-set therefore provides a direct drive between the crank-shaft I6 and the planet-carrier.

Should the sun gear I!) be engaged with the sun gear II when the starter-generator 25 begins to operate as a motor, the tendency of the sun gear II) to rotate in a counterclockwise direction will cause the ratchet teeth 3I32 to force it to the left into clutching engagement with the stationary collar 21.

It may be noted that the slope of each of the two sets of ratchet-teeth and 3I--32 is determined by the direction in which the driving and driven elements rotate and by whether the speedchanging drive is to be a speed-reducing or a speed-increasing drive. As shown, the speedchanging drive is a speed-reducing drive and is obtained when the planet-carrier is the driving element; but by reversing the direction in which the clutch teeth slope (or by reversing the direction of rotation) a direct drive would be obtained with the planet carrier i2 as the driving element and a speed-increasing drive would be provided when the sun gear II was the driving element.

To prevent any harmful consequences should complete movement of the gear II] to either of its limit positions be prevented by end-to-end engagement of the clutch teeth, one of the two elements I I and 21 may be capable of yieldingly opposed sliding movement on the sleeve I8. In the drawing, the sun gear I I is shown as so arranged, it being held in normal position against a shoulder I8 by a spring 43. Should the teeth 3I32 engage each other in abutting rather than meshing relation when ratchet action of the teeth 3| is forcing the sun gear Ill to the right, the spring 40 will yield momentarily to permit relative rotation of the two sun gears until the clutch teeth are brought into meshing relationship.

The yieldable mounting of the sun gear II on the sleeve I8 also acts to prevent any damage should complete leftward movement of the sun gear I!) be prevented by end-to-end engagement of the teeth 30; for any resistance to leftward movement of the gear I0 would be reflected as rightward pressure imposed on the gear II through the teeth 3I--32, and the gear II could yield against the force of the spring 40 under the influence of that rightward pressure.

The resistance with which the snap-ring opposes movement of the small sun gear ID from either of its limit positions should be proportioned to the torque which the gear-set transmits, so that such resistance will never be so great as to prevent the intended axial movement of the sun gear I0.

While I have shown a gear-set of particular form as employed to interconnect an internal combustion engine with a starter-generator, it is to be understood that my invention is not limited to such an application nor to the particular form of gear-set shown.

I claim as my invention:

1. In combination with an internal combustion engine, a starter-generator, and means operatively interconnecting said engine and said starter-generator, said means including a planetary gear-set having two relatively rotatable, coaxial sun gears of different sizes and a planetgear carrier carrying pinions operatively interconnecting said sun gears, said planet-carrier and the larger of said two sun gears being operatively connected to said starter-generator and said engine respectively, a stationary part, and means responsive to the direction in which the smaller sun gear tends to rotate for clutching it either to said stationary part or to said larger sun gear.

2. In combination with an internal combustion engine, a starter-generator, and means operatively interconnecting said engine and said starter-generator, said means including a planetary gear-set having two relatively rotatable, coaxial sun gears of different sizes and a planet-gear carrier carrying pinions operatively interconnecting said sun gears, said planet-carrier and the larger of said two sun gears being operatively connected to said startengenerator and said engine respectively, a stationary part, and means responsive to the direction in which the smaller sun gear tends to rotate for clutching it either to said stationary part or one of the other elements of said gear-set.

3. In combination with an internal combustion engine, a starter-generator, and means operatively interconnecting said engine and said starter-generator, said means including a planetary gear-set having two relatively rotatable, coaxial sun gears of different sizes and a planetgear carrier carrying pinions operatively interconnecting said sun gears, said planet-carrier and the larger of said two sun gears being operatively connected to said starter-generator and said engine respectively, a stationary part, and means responsive to the direction in which the smaller sun gear tends to rotate for clutching it to said stationary part when said startergenerator is driving said engine and for clutching it to another element of said gear-set when said engine is driving said starter-generator.

4. In combination with an internal combustion engine, a starter-generator, and means operatively interconnecting said engine and said starter-generator, said means including a planetary gear-set having two relatively rotatable, coaxial sun gears of different sizes and a planetgear carrier carrying pinions operatively interconnecting said sun gears, said planet-carrier and the larger of said two sun gears being operatively connected to said starter-generator and said engine respectively, a stationary part, said stationary part and said smaller sun gear being provided with a set of cooperating ratchet clutch teeth, said two sun gears being provided with a second set of co-operating ratchet clutch teeth, and said smaller sun gear being mounted for axial sliding movement between positions in which said two sets of clutch teeth are respectively engaged, said first set of clutch teeth being inclined to move said smaller sun gear out of association with said stationary part and into clutching engagement with the larger sun gear when the engine is driving the generator, and said second set of clutch teeth being inclined to move said smaller sun gear out of association with the larger sun gear and into clutching enstarter-generator is driving the engine.

J ARL M. WEYDELL. 

